共查询到20条相似文献,搜索用时 15 毫秒
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给出了一组描述同轴回旋行波放大器中波束相互作用的非线性自洽方程组,对该放大器的运行特性进行了研究。得到:在小信号区,辐射场的增益随同轴波导的内外半径比b/a的增加而增加,达到饱和时的辐射功率仅略有下降;内外导体管壁上的功率损耗密度随b/a的增加而减小。采用电压为90kV,电流为10A,纵向速度零散度为3%,速率比为1的电子束,在34.26~36.78GHz的频率范围内,计算得到了峰值功率约230kW的微波输出,相应的增益和效率分别为46.6dB和25.5%,带宽为7%,内外导体管壁上功率的最大损耗分别为80和56W/cm2。 相似文献
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A simple scheme is proposed for the construction of a wide-band fast wave gyrotron travelling wave amplifier. The key features of this scheme include a contoured waveguide, a tapered magnetic field, and injection of input signals in opposite direction of the streaming electrons. Bandwidths at tens of percents, and gain at tens of decibals, are projected. 相似文献
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本文阐述了半导体激光放大器组件中,末端带高折射率类球透镜的锥形光纤耦合头对放大器芯片的外腔反馈效应,从理论上对这种耦合头的反馈效应进行了计算.为了使计算结果更接近于实际情况,在理论分析中引入了厚透镜表面的菲涅耳(Fresnel)反射及有限孔径的影响. 相似文献
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Y. Y. Lau K. R. Chu L. Barnett V. L. Granatstein 《International Journal of Infrared and Millimeter Waves》1981,2(3):395-413
The small signal gain and bandwidth of the gyrotron travelling-wave amplifier (gyro-TWA) operating at the fundamental cyclotron harmonic are examined. The analytical and numerical studies focus on the effects of velocity spread in the electron beam and of a distributed wall resistivity in the waveguide. It is found that wall resistivity reduces the forward gain of the amplifier only by an amount approximately equal to 1/3 of the corresponding cold tube loss. Significant increase in bandwidth may result, under certain conditions, from the presence of wall resistivity. A moderate amount (5–10%) of velocity spread does not reduce the peak gain significantly in general, but may reduce the bandwidth by an amount depending on the applied magnetic field. Based on considerations of such factors as power, stability, gain, bandwidth, and efficiency, operating parameters for the gyro-TWA are suggested. 相似文献
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回旋行波管放大器是一种具有高功率、高频率、宽带宽的毫米波放大器,TE02模二次谐波回旋行波管放大器在保持基波回旋行波管放大器的基础上极大地减小了工作磁场,从而具有广阔的应用前景. 利用两段分布式损耗的互作用结构,有效抑制了绝对不稳定性和回旋返波振荡,避免了模式互作用电路引起的模式畸变,提高了输出功率,在一定程度上克服了谐波互作用较弱的缺点,满足了扩展功率容量和放大器长时间稳定工作的要求. 非线性模拟结果和粒子模型(particle in cell)模拟结果均表明,在工作电压为100k
关键词:
W波段
二次谐波
回旋行波管放大器 相似文献
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回旋行波管放大器是高功率毫米波雷达发射系统最重要的候选者.通过对回旋行波管放大器中的绝对不稳定性、回旋返波振荡以及电子注-波互作用的研究,讨论了回旋行波管的稳定性、寄生模式的抑制和工作参数的优化等问题,给出了W波段TE01模回旋行波管放大器的模拟设计结果.PIC粒子模拟结果表明,在电子注电压100kV、电流10A、工作磁场3.52T时,94GHz的基波回旋行波管放大器可获得大于250kW的输出功率、40dB的增益、大于25%的效率和约5%的带宽.
关键词:
W波段
回旋行波管放大器
模拟
设计 相似文献
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建立了由损耗段和铜段组成的波导结构的Ka波段二次谐波回旋行波放大器理论模型,并进行了非线性理论研究。基于稳定性分析,确定35 GHz TE02模二次谐波回旋行波放大器的基本工作参数:波导半径为1.02 cm,电子注工作电压为90 kV,工作电流为25 A,工作磁场为0.642 6 T,横纵速度比为1.2;然后通过模拟详细分析了工作电流、波导损耗和速度零散等因素对该放大器性能的影响。研究表明:在该结构中损耗段可以有效地抑制模式竞争从而提高输出功率和带宽;工作电流对输出功率的影响存在最大值;速度零散对输出功率有很大的影响。 相似文献
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W-Band Second-Harmonic Gyrotron Traveling Wave Amplifier with Distributed-Loss and Severed Structures 总被引:2,自引:0,他引:2
Yi Sheng Yeh Chien Lun Hung Chi-Wen Su Ting-Shu Wu You-Yan Shin Yu-Tsung Lo 《International Journal of Infrared and Millimeter Waves》2004,25(1):29-42
The second harmonic TE02 gyrotron traveling wave amplifier (gyro-TWT) is a high-power, broadband, millimeter-wave amplifier with a low applied magnetic field. Mode-selective interaction circuits were applied to suppressing spurious oscillations. However, the mode-selective interaction circuit may perturb the operating mode in the gyro-TWT. A multi-stage gyro-TWT design with distributed-loss and severed structures is proposed to stabilize the amplification. This study presents a nonlinear analysis of typical oscillations, including absolute instability, gyrotron backward oscillation (gyro-BWO) and reflective oscillation. The lossy and severed sections of the multi-stage gyro-TWT seem to increase effectively the start-oscillation currents of the absolute instability, gyro-BWO, and reflection oscillation. The multi-stage gyro-TWT is predicted to yield a peak output power of 215 kW at 89.9 GHz with an efficiency of 14.3 %, a saturated gain of 60 dB and a bandwidth of 1.7 GHz for a 100 kV, 15 A electron beam with an axial velocity spread
z/
z = 5%. 相似文献
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详细推导了具有分布损耗波导结构的回旋行波放大器的色散特性。通过绝对不稳定性振荡出现的条件,给出求解具有损耗波导结构回旋行波管放大器的绝对不稳定性起振电流的数值计算方法。研究结果表明:绝对不稳定性起振电流与损耗波导的集肤深度有关,选择有较大的集肤深度的损耗波导可以提高绝对不稳定性起振电流;绝对不稳定性起振电流同时也与工作磁场偏离饱和磁场的程度以及电子束的纵横速度比有关;通过设计具有分布损耗波导结构的注-波互作用电路,以及工作磁场、电子束的纵横速度比,可以在兼顾带宽、效率的条件下,保证回旋行波管放大器稳定工作。 相似文献
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以Barkley模型为研究对象, 研究了在时空调制作用下螺旋波时空动力学行为特性. 发现在适当的调制参数的作用下, 能够在同一系统中同时观察到漫游螺旋波与旅行螺旋波. 通过数值模拟研究分析, 给出了能产生漫游螺旋波与旅行螺旋波共存现象的潜在机理, 并详细讨论了在Barkley 模型中要产生这种共存现象的两个必要条件.
关键词:
时空调制
漫游螺旋波
旅行螺旋波 相似文献
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A helix type slow wave structure filled with plasma is immersed in a strong
longitudinal magnetic field. Taking into account the effect of the plasma and the
dielectric, the system is separated radially into three regions. By means of
the sheath model and Maxwell equation, the distribution of the electromagnetic
field is established. Using the boundary conditions of each region, the dispersion
relation of the slow wave structure is derived. The trend of change for the radial
profile of the axial electric field is analysed respectively in different plasma
densities, plasma column radius and dielectric constant by numerical computation.
Some useful results are obtained on the basis of the discussion. 相似文献
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Chenglin Bai 《Reports on Mathematical Physics》2004,53(2):291-299
A method to construct the new exact solutions of nonlinear partial differential equations (NLPDEs) in a unified way is presented, which is named an improved sine-cosine method. This method is more powerful than the sine-cosine method. Systems of dispersive long wave equations in (1+1) and (2+1) dimensions are chosen to illustrate the method and several types of explicit and exact travelling wave solutions are obtained. These solutions contain Wang's results and other types of solitary wave solutions and new solutions. The method presented here is general and can also be applied to solve more systems of nonlinear partial differential equations, such as the coupled KdV equations. 相似文献
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Dielectric effect on the rf characteristics of a helical groove travelling wave tube 总被引:1,自引:0,他引:1 下载免费PDF全文
A new type of partial-dielectric-loaded helical groove slow-wave structure (SWS) for millimetre wave travelling wave tube (TWT) is presented in this paper.The radio-frequency characteristics including the dispersion properties,the longitudinal electric field distribution and the beam-wave coupling impedance of this structure are analysed.The results show that the dispersion of the helical groove circuit is weakened,the phase velocity is reduced and the position of the maximum Ez is moved from the mouth to the inside of the groove after partially filling the dielectric materials in the helical groove SWS.Therefore,the dielectric-loaded helical groove SWS is suitable for a multi-beam TWT with broad band and high gain. 相似文献
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On the basis of a rigorous field theory, two different physical models of attenuator and sever have been proposed. One is named High attenuation (HATT) model in which both attenuator and sever are considered as a unified attenuator, but the sever is regarded as an area of very high loss; the other is called Sever and attenuator (SATT) model in which the sever is modelled as a drift area in which the electric and magnetic fields both vanish. A complex function is derived and potential sinking effect is also considered. Thus, a set of more practical self-consistent equations of nonlinear beam-wave interaction is formulated. Simulations are carried out under the conditions of the two different physical models, and the simulation results are compared with the experimental data. The results show that in the case of single signal drive, the unknown second harmonic should be included for predicting the saturated output power. It is also evident that the SATT model and the HATT model predict the same physical nature, whereas the results predicted by the HATT model are much closer to the experimental data than those obtained from the SATT model. Therefore, these results provide a strong theoretical basis for designing broadband and high gain helix travelling wave tubes. 相似文献